Wow, thanks, that totally cleared it up for me. The Sony is more than sufficient for what I'd need. It seems like I'm going to cancel my nook order ("This deal just keeps getting worse and worse all the time.") and get the Sony. The picture of the baby totally sold me: if the 16 shades looks better, who cares, it's totally good enough.
And, I've pretty much got a $260 limit (I can get the Sony for 10% off with a faculty discount). The iRex looks sweet, but I could buy 3 Sony's and tape them together for the same price :P